CDC 6600’s Five Year Reign

The 6600 had 400,000 transistors and more than 100 miles of wiring. In addition to a blazingly fast floating-point processor, it had 10 “peripheral processors” that did housekeeping and input/output tasks at the same time.

CDC 6600's Five year Reign

The CDC 6600 toppled speed records in 1964. Control Data sold about 100 of them, penetrating markets beyond the usual government and military customers.

The 6600 executed a dizzying 3,000,000 instructions per second. Designed by supercomputer pioneer Seymour Cray, it wasn’t surpassed until the CDC 7600 in 1969—another Cray design.

Before integrated circuits, "cordwood" modules let engineers pack components into small spaces, increasing speed by keeping wires shorter. Seymour Cray's early computers all used this construction. In the 6600, metal plates in contact with circulating Freon™ cooled the cordwood modules.

Seymour Cray's CDC 6600 design was innovative and elegant. Almost 10 times faster than any computer ever devised, it stunned the computing community. Customers wrote their own applications, from simulating explosions to timesharing, weather forecasting, and much more.

But IBM never actually shipped its “6600 killer,” and CDC president William Norris responded with an antitrust suit. Four years later IBM settled, giving CDC cash and ownership of a computer services company, together worth over $600M.

Watson penned this scathing memo asking how IBM lost “our industry leadership” to a company with “34 people, including the janitor.” Also known as "The Janitor Memo," it shows the impact Control Data Corporation and its computers had on the leadership of IBM.